When in Doubt, Look Up! StormSensor Investigates Weather Lore

The holidays are a great time for stories and legends, and because we at StormSensor spend most of time thinking about rain, the effects of the rain, and when it will rain next, we thought we’d investigate some weather folklore and see how they hold up to our rigorous standards.

People have always looked to animals—both large and small—to predict the weather:

When cows lie down, it’s about to rain

Guys, this has been scientifically studied—THEY PUT PEDOMETERS ON COWS! The basic conclusion is that cows like to stand up when they are hot, because it’s easier to cool down that way. The reverse concept, that they lie down when they are cool (and the logical leap to the idea the cool cows somehow indicate rain), is not necessarily true. Cows lie down for the same reasons we do, to rest! Dr. Jamison Allen, who completed the study,suggests watching the news (instead of the cows) if you’d like to know the chance of rain.

The more black on wooly bear caterpillars, the more severe the winter will be

This lore actually started with a (vaguely) scientific study. From 1948 to 1956, Dr. C.H. Curran, then the curator of insects at the American Museum of Natural History, collected wooly bear caterpillars and noted that the more brown they were, the milder the winter, and the more black they were, the more severe the winter would be. Of course, there is a problem with sample size for such a sweeping conclusion, but some scientists think there could actually be just a little truth to this idea. The colors on the caterpillar correspond with its age—the number of brown hairs has to do with how early the caterpillar was able to get hatched and going in the spring, which actually tells us something about the previous winter, so they are more of a record than a prediction, similar to how we view tree rings.

Sometimes catching up to an animal is tricky—but we’ve heard the plants have done a little forecasting as well:

When leaves turn their backs it’s about to rain

According to the National Park Service, there is some truth to this one! Some trees have leaves that tend to curl up when there is high humidity and strong winds, both signs that a storm is approaching. (Although we think you might notice those signs before you have a chance to run out and check the leaves!)

Persimmon seeds can predict the severity of the upcoming winter

Many regions in the U.S. use persimmon seeds to predict how much snow and ice they’ll get in the upcoming winter. According to this legend, a seed with a spoon shape means there will be lots of snow, a knife shape means lots of ice, and a fork shape means a mild winter. We could not find any scientific studies to verify or dispel this one. However, Kevin Ambrose at the Washington Post did some investigative journalism last year in the D.C. area and predicted a snowy winter. We went ahead and checked the records and it turns out the D.C. area actually received less than average snowfall last year. Sorry: this myth is busted (but we’re told persimmons are delicious—so by all means, go ahead and keep eating them).

When all else fails- look up! These weather forecasting tools were the ones sailors used to bet their lives on:

Mackerel sky, mackerel sky, never long wet, never long dry

The “Mackerel Sky” in this old sailors’ proverb refers to a pattern of clouds that look like fish scales. These clouds indicate a weather front high up in a cold sky. These clouds are often associated with another form of cloud, the mare’s tail, which is indicative of high winds aloft. So, when we see these patterns together, we can expect rainy weather to arrive soon, but we can also expect it to move along quickly. This one checks out—those sailors knew a thing or two, but we’d still recommend that you check a weather model for a more accurate description of “soon” and “quick”.

Halo around the moon; snow or rain will come soon

On a clear night, you can sometimes see a halo, or ring, around the moon. This phenomenon is caused by light refracting within the ice crystals of high cirrus clouds, 20,000 to 30,000 ft. aloft. These high cirrus clouds often signal an approaching weather front, so, while the sky may be clear when you view the halo, it is a signal that change is on the way! Want to know what kind of change? Seek out a meteorologist.

The Final Verdict

People throughout the ages have always used the best tools they had at their disposal to make sense of the world around them. We have satellite data and barometers; they had cows and leaves! We all owe a debt of gratitude to those who set sail across the sea with stars for a map and clouds for a forecast. It’s amazing that many of these legends have at least a grain of truth to them, and understanding the science behind them can help us be more observant and appreciative as we explore our modern world—secure in the knowledge that we can always double check with a weather app!

About the author

Suzie Housley

Suzie has over a decade of experience in the Stormwater industry including both government and academic work. She leans on her experience to meaningfully interpret scientific studies and government policies to communicate a practical message. Suzie lives just outside Nashville, TN and gets outside whenever she can to explore nature with her husband and two small children.